JP2014122047A - Laminate film for shrink packaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film for shrink packaging which can be used for shrink packaging and enhance a function of a packaged products.SOLUTION: A laminate film includes paired shrink films 1a, 1b having heat shrinkability, and a connection layer CL arranged between the paired shrink films 1a, 1b, thicknesses of the respective shrink films 1a, 1b are 9.5-15 μm, and the total thickness is 19.5-35 μm. Since the thickness of the laminate film itself for shrink packaging is 19.5-35 μm, it can be used for shrink packaging. Moreover, since the paired shrink films overlap each other, the laminate film has a strength larger than a conventional film for shrink packaging to be hardly broken when an over-wrap packaging.

Description

  The present invention relates to a laminate film for shrink wrapping. More specifically, the present invention relates to a shrink-wrapping laminate film used for packaging in a state where the packaging film is in close contact with the packaging article.

  When selling products such as food, confectionery, books, cosmetics, and pharmaceuticals, the products are provided and sold in a state of being packaged with a plastic film or the like in order to prevent the product from being soiled. There are various types of packaging for such packaging. When automatic packaging is performed on a production line, for example, shrink packaging (heat shrink packaging) can be mentioned.

  Shrink wrapping (heat-shrink wrapping) allows (1) packaging with a film in close contact with the packaged article regardless of the shape of the packaged article, etc. (2) Packaging with multiple articles fixed and held together (3) It has the merit that automation of packaging is easy. For this reason, shrink wrapping has been increasingly used for packaging various articles to be packaged.

By the way, although shrink wrapping is packaged by a single layer film, in order to obtain an improvement in appearance and an advertising effect, various patterns and characters are printed on the wrapping film itself. This printing is designed in consideration of the appearance when the film is thermally contracted.
In addition, light-shielding ink or the like may be printed in order to prevent the inner packaged article from being deteriorated by light.

  On the other hand, when shrink-wrapping, the film is heat-sealed in order to seal the packaged article with the film. Thermal fusion is usually performed at the same time as the film is cut by a known sealing machine such as a fusing seal or a palm seal, but printing is performed on the surface located outside when the packaged article is packaged with the film. In this case, the printing ink melts and adheres to the sealing machine at the time of sealing, which may contaminate the sealing machine. On the contrary, when printing is performed on the surface located inside when the article to be packaged is packaged with the film, the printing ink becomes an obstacle and the heat fusion between the films is inhibited.

For this reason, in the film used for shrink wrapping, the printing design is adjusted so that there is no printing ink in the portion to be heat-sealed. Then, there is a problem that the design of the product is not good because the print design is limited and there is no printing at the heat-sealed portion.
Further, even when the film is provided with a light-shielding property, there is a problem that a sufficient light-shielding property cannot be provided because printing cannot be performed on the heat-sealed portion.

  As a method for preventing such a problem, it is conceivable to prevent the printing ink from being exposed on the surface. For example, in a shrink label or the like, a technique for printing on the back surface of the shrink film (that is, the surface on the heat shrink sheet side) as a laminated sheet by laminating the shrink film and the heat shrink sheet is developed (for example, Patent Documents 1 to 3). 5).

Japanese Utility Model Publication No. 60-62936 Japanese Utility Model Publication No. 63-43722 Japanese Patent Laid-Open No. 3-219952 JP-A-4-41233 JP-A-8-300547

However, the techniques of Patent Documents 1 to 5 are techniques related to sheets used for shrink labels, and the thickness thereof is very large. For example, if the heat-shrinkable sheet is a foamed urethane sheet, the thickness is several hundred μm or more. Such a sheet cannot be used for shrink wrapping which is sealed by heat sealing.
In the techniques of Patent Documents 1 to 5, as a matter of course, no consideration is given to the above-described problem of thermal fusion.

  At present, only a single-layer film is used in shrink wrapping, and in a laminated film formed to a thickness that can be used for shrink wrapping, there is no film printed up to the heat-sealed part, Such a film is desired.

  In view of the above circumstances, an object of the present invention is to provide a laminate film for shrink wrapping that can be used for shrink wrapping and can improve functions such as appearance and light shielding properties of the packaged product.

  The laminate film for shrink packaging of the first invention comprises a pair of shrink films having heat shrinkability, and a connecting layer provided between the pair of shrink films, and the thickness of each shrink film is as follows: It is 9.5-15 micrometers, and the whole thickness is 19.5-35 micrometers, It is characterized by the above-mentioned.

  According to 1st invention, since the thickness of the laminate film for shrink packaging becomes 19.5-35 micrometers, it can be used for overlap packaging. Moreover, since the two shrink films are overlapped, the strength can be increased as compared with the film used in the conventional overlap packaging. Therefore, it becomes difficult to tear when overlap-wrapped.

It is a schematic sectional explanatory drawing of the laminate film 1 for shrink packaging of this embodiment. It is a schematic explanatory drawing of the manufacturing equipment of the laminate film 1 for shrink packaging of this embodiment. It is a schematic explanatory drawing of the operation | work which manufactures package body MP using the laminate film 1 for shrink packaging of this embodiment.

  The laminate film for shrink wrapping of the present invention is a film used for shrink wrapping articles to be packaged, and can improve functions such as appearance and light shielding properties of shrink-wrapped products.

  The article to be packaged that is shrink-wrapped by the shrink-wrapping laminate film of the present invention is not particularly limited. For example, food, confectionery, books, cosmetics, pharmaceuticals, and the like can be mentioned, but the invention is not limited to these.

  The laminate film for shrink wrapping of the present invention is very thin as compared with the packaged article, and the film and each layer constituting the laminate film for shrink wrapping are also very thin. The relative dimensions of packaging articles, etc., the film thickness of the cross section of the laminate film for shrink packaging, the thickness of each layer, and the like do not necessarily match the actual relative dimensions.

  Moreover, the laminate film for shrink packaging of the present invention has at least a pair of shrink films as will be described later, but the number of shrink films constituting the laminate film for shrink packaging is not limited to two. For example, the laminate film for shrink wrapping of the present invention includes a laminate of three or more shrink films. In addition, when three or more shrink films are laminated, it is not necessary to provide a printing layer and an adhesive layer between all the shrink films, and only an adhesive layer may be provided. .

(Laminate film for shrink wrapping)
The shrink wrap laminate film 1 of this embodiment will be described.

As shown in FIG. 1, a laminate film 1 for shrink wrapping according to this embodiment includes a pair of shrink films 1a and 1b, and a printing layer 2 and an adhesive layer 3 formed between the pair of shrink films 1a and 1b. The coupling layer CL is composed of
And the laminate film 1 for shrink packaging of this embodiment uses a thing with a thickness of about 9.5-15 micrometers as a pair of shrink film 1a, 1b. Therefore, the total thickness of the laminate film for shrink wrap 1 including the pair of shrink films 1a and 1b and the connecting layer CL can be set to about 19.5 to 35 μm.
For this reason, the thickness of the laminate film 1 for shrink wrapping according to this embodiment can be set to a thickness equivalent to that of a single layer film used for conventional shrink wrapping. Then, like the conventional single layer film, it can be used for overlap packaging.
Moreover, since the two shrink films are overlapped, the strength is higher than that of the conventional shrink wrap film, so that there is an advantage that it is difficult to break when overlap wrap.

  Moreover, in the laminate film 1 for shrink packaging of this embodiment, the printing layer 2 is pinched | interposed with a pair of shrink films 1a and 1b.

  For this reason, in the case of the laminate film 1 for shrink wrapping of the present embodiment, when the upper and lower films Fa and Fb are fused or heat-sealed in the manufacturing process of the package MP as described later, the film is printed at that position. Even if there is a portion that is present, that is, the printing layer 2, the material such as printing ink of the printing layer 2 does not directly contact the sealing machine. That is, since a material such as printing ink does not adhere to the sealing machine, the sealing machine or the like does not get dirty even if there is printing on the heat-sealed portion.

Furthermore, if there is printing on the portion to be heat-sealed, printing ink or the like may inhibit the heat-sealing.
However, if the material of the printing layer 2 contains a chlorinated polypropylene resin, even if the printing layer 2 is present at the portion to be heat-sealed, it can be firmly heat-sealed.
Then, in shrink wrapping, for example, overlap wrapping, it is not necessary to make the area to be heat-sealed as a non-printing area. Therefore, the degree of freedom in designing the printed layer is increased and the entire surface can be printed. In addition, functions such as the appearance and light-shielding properties of the products that are wrapped and wrapped can be improved.

Below, each member of the laminate film 1 for shrink wrapping of this embodiment is demonstrated.
In the following description, among the pair of shrink films 1a and 1b, the shrink film 1a is disposed outside the packaging body MP, and the shrink film 1b is disposed inside the packaging body MP, that is, on the side in contact with the packaged article M. The case where it will be described.

(Shrink film)
First, the pair of shrink films 1a and 1b are formed of a resin that has heat shrinkability and can be heat-sealed in a state where the films are stacked. That is, the pair of shrink films 1a and 1b is thermally melted in any state of the state in which the shrink films 1a are overlapped, the state in which the shrink films 1b are overlapped, and the state in which the shrink film 1a and the shrink film 1b are overlapped. It can be worn.

  In addition, a pair of shrink film 1a, 1b should just have the above properties, and is not specifically limited. Examples thereof include a film obtained by uniaxially or biaxially stretching a resin film such as polypropylene (PP) or polyethylene terephthalate (PET).

  In addition, it is preferable that the pair of shrink films 1a and 1b be formed with the same resin and the same thickness because the shrinkage ratios of both the shrink films 1a and 1b can be made substantially equal when thermally contracted. Moreover, since the curl does not generate | occur | produce when the laminate film 1 for shrink packaging heat shrinks, it is preferable.

(Linking layer CL)
As described above, the coupling layer CL is composed of the printing layer 2 and the adhesive layer 3, but the printing layer 2 may not be provided.
The printing layer 2 can be formed by applying a printing ink containing a pigment, a solvent, and a binder to the back surface of the shrink film 1a by a method such as gravure printing or flexographic printing. In addition, the chlorinated polypropylene resin mentioned above can be contained in printing ink as a binder or in addition to a well-known binder.

(Adhesive layer 3)
The adhesive layer 3 is a layer formed on the back surface of the shrink film 1b. The adhesive layer 3 is formed by applying an adhesive such as a urethane adhesive or a chlorinated polyolefin adhesive (for example, chlorinated polypropylene resin) to the back surface of the shrink film 1b by a method such as gravure coating. Has been.

In addition, the application amount of the adhesive layer 3 is not particularly limited, but for example, it is preferable to apply 1 g / m ² or more.

  Moreover, it is preferable to apply | coat an adhesive agent after performing the surface treatment for improving adhesiveness with an adhesive agent to the shrink film 1b. Examples of the surface treatment include corona discharge treatment and plasma treatment.

(Manufacturing method of the laminate film 1 for shrink packaging of this embodiment)
Below, the method to manufacture the laminate film 1 for shrink packaging is demonstrated.
In FIG. 2, symbols MR1 and MR2 are original rolls around which the above-described shrink film 1a and shrink film 1b are wound. Moreover, the symbol SR is a product roll around which the manufactured laminate film 1 for shrink wrapping is wound.
In addition, when the shrink film 1a has the printing layer 2, the printing layer 2 is previously formed in the shrink film 1a wound up by the original fabric roll MR1.

  First, the shrink film 1a is unwound from the raw roll MR1 and supplied to the laminating apparatus RP.

  On the other hand, when the shrink film 1b is unwound from the raw roll MR2, the surface treatment is performed on the back surface (lower surface in FIG. 2) by the surface treatment device CP.

The shrink film 1b surface-treated by the surface treatment device CP is supplied to the adhesive application device GR, and the adhesive is applied to the back surface, that is, the surface-treated surface, so that the adhesive layer 3 is formed.
In addition, in order to apply | coat an adhesive agent uniformly to the shrink film 1b, it apply | coats in the state melt | dissolved in the solvent. What is necessary is just to use the solvent used in this case according to an adhesive agent.

  The shrink film 1b on which the adhesive layer 3 is formed is supplied to the drying device DP. In the drying device DP, the shrink film 1b is heated to remove the solvent contained in the adhesive layer 3 formed on the shrink film 1b.

Then, the shrink film 1b that has passed through the drying device DP is supplied to the laminating device RP, and is laminated and bonded to the shrink film 1a. Specifically, in the laminating apparatus RP, the surface of the shrink film 1b on which the adhesive layer 3 is formed and the surface on which the printed layer 2 of the shrink film 1a is formed are pressed together. Then, both sheets are adhere | attached with the adhesive agent of the adhesive bond layer 3, and the laminate film 1 for shrink wrapping is formed.
(Method for producing package MP)
Below, the process of manufacturing package MP which was shrink-wrapped with the laminate film 1 for shrink-wrapping of this embodiment is demonstrated easily.

  In the process of manufacturing the package MP, the laminate film 1 for shrink wrapping according to the present embodiment is a continuous belt-like web, and two such that a space is formed between the upper and lower films Fa and Fb in the transport process. Can be folded. Then, the packaged article M is supplied to the space between the upper and lower films Fa and Fb, and the packaged article M is sandwiched between the upper and lower films Fa and Fb (see FIG. 3A).

  When the article to be packaged M is sandwiched between the upper and lower films Fa and Fb, the laminate film 1 for shrink wrapping is heated and cut by the well-known fusing seal at the portions located before and after the article to be packaged M in the transport direction. Is done. At this time, the portion cut by the fusing seal is fused and the upper and lower films Fa and Fb are heat-sealed to form a heat-sealed portion HS. At the same time, the opening edges s of the upper and lower films Fa and Fb are heat-sealed to form a heat-sealing part HS. That is, the upper and lower films Fa and Fb are heat-sealed to form a heat-sealed portion HS on three sides surrounding the packaged article M excluding the portion where the laminate film 1 for shrink wrapping is bent. . That is, the pre-shrinkage packaging body BS in which the packaging article M is sealed is formed by the shrink wrapping laminate film 1 (see FIG. 3B). As described above, if the laminate film 1 for shrink wrapping has the printing layer 2 and the printing layer 2 contains a chlorinated polypropylene resin, the upper and lower films Fa and Fb are formed in the heat fusion part HS. They can be firmly heat-sealed together.

  The pre-shrink wrapping body BS formed as described above is conveyed by a conveyor or the like and supplied to a heating tunnel or the like. Then, when passing through this heating tunnel or the like, the shrink wrapping laminate film 1 shrinks due to heating, so that the packaging body MP in which the shrink wrapping laminate film 1 is in close contact with the surface of the packaged article M is formed. (See FIG. 3C).

Whether or not shrink wrapping is possible with the laminate film for shrink wrapping of the present invention was confirmed by heat shrinking the laminate film for shrink wrapping.
In the experiment, the shrinkage ratio (MD / TD (%)) after immersing the laminate film for shrink packaging in a glycerin bath for 10 seconds was measured.

  The laminate film for shrink wrapping used in the experiment is that each shrink film is a polypropylene film (thickness 15 μm), and the total thickness is 32 μm bonded together using an adhesive (urethane adhesive). 2 is formed by equipment as shown in FIG.

  As a reference example, the heat shrinkage of the polypropylene film (thickness 15 μm) used in the examples when immersed in a glycerin bath for 10 seconds was confirmed.

The results are shown in Table 1.
As shown in Table 1, both Examples 1 and 2 show shrinkage similar to that of the single-layer film of the reference example.
From this, in the laminate film for shrink wrapping of the present invention, it can be determined that shrink wrapping is possible as in the case of the conventional single-layer film, provided that the shrinkage rate is in an appropriate range.

  The laminate film for shrink packaging of the present invention is suitable as a film for overlapping packaging of articles to be packaged such as food, confectionery, books, and medicines.

DESCRIPTION OF SYMBOLS 1 Laminate film for shrink packaging 1a Shrink film 1b Shrink film 2 Print layer 3 Adhesive layer CL Connection layer

Claims (1)

A pair of shrink films having heat shrinkability;
A connection layer provided between the pair of shrink films,
Each shrink film has a thickness of 9.5 to 15 μm,
A laminate film for shrink wrapping, wherein the total thickness is 19.5 to 35 μm.